Traitement des neuropathies amyloïdes héréditaires

The transthyretin amyloidoses: advances in therapy

There are two forms of transthyretin (TTR) amyloidosis: non-hereditary and hereditary. The non-hereditary form (ATTRwt) is caused by native or wild-type TTR and was previously referred to as senile systemic amyloidosis. The hereditary form (ATTRm) is caused by variant TTR which results from a genetic mutation of TTR. The predominant effect of ATTRwt amyloidosis is on the heart, with patients having a greater left ventricular wall thickness at presentation than the devastating form which is light chain (AL) amyloidosis. ATTRm amyloidosis is broadly split into two categories: a type that predominantly affects the nervous system (often called familial amyloid polyneuropathy (FAP)) and one with a predilection for the heart (often called familial amyloid cardiomyopathy (FAC)). Approximately half of all TTR mutations known to express a clinical phenotype cause a cardiomyopathy. Since the introduction of orthotopic liver transplantation for ATTRm amyloidosis in 1991, several additional therapies have been developed. These therapies aim to provide a reduction or elimination of TTR from the plasma (through genetic approaches), stabilisation of the TTR molecule (to prevent deposition) and dissolution of the amyloid matrix. We describe the latest developments in these approaches to management, many of which are also applicable to wild-type amyloidosis.

[Liver transplantation as treatment of familial amyloid polyneuropathy in patients older than 60 years]

BACKGROUND AND OBJECTIVE

Familial amyloid polyneuropathy (FAP) is the most prevalent type of hereditary systemic amyloidosis. It is an autosomal dominant disease characterized by the deposition of an abnormal variant transthyretin. It has a worldwide distribution, with localized endemic areas in Portugal, Sweden and Japan. In Spain there is an endemic focus, located in Mallorca. Liver transplantation is the only curative option for patients with FAP. The aim of this study was to describe the clinical and demographic characteristics of patients transplanted with a diagnosis of PAF.

MATERIAL AND METHOD

Six patients with PAF underwent liver transplantation between April 1986 and December 2012.

RESULTS

The mean age was 57.7+16 years, patients of Spanish origin were older than 60 years. All patients had progressive symptoms as mixed polyneuropathy. In 2 patients, combined heart-liver transplants sequentially were performed. Patient survival and graft was 80% at one, 3 and 5 years.

CONCLUSIONS

The only effective treatment for etiologic PAF is liver transplantation. Early detection is the key to the treatment and control, avoiding the irreversible organ damage.

Epidemiology of transthyretin-associated familial amyloid polyneuropathy in the Majorcan area: Son Llàtzer Hospital descriptive study

Background

Transthyretin-associated Familial Amyloid Polyneuropathy (TTR-FAP) is an autosomal dominant disease caused by the deposition of abnormal transthyretin that results from a gene mutation. Although rare worldwide, there are descriptions of several endemic foci, such as in Majorca, Balearic Islands, Spain. We aimed at describing a contemporary series of TTR-FAP patients in Son Llàtzer Hospital in Majorca from an epidemiological point of view in order to report their main clinical and laboratory characteristics.

Methods

A retrospective, observational study was performed. Medical records from adult patients diagnosed with TTR-FAP from a single hospital were reviewed.

Results

Out of a total of 107 cases, 75 subjects were included: asymptomatic carriers (52.3%) and symptomatic patients (47.7%). Mean age was 58.3 years at the time of the study, and 50.7% were men. Mean age at diagnosis was 49.8 years. In addition, 42 patients (39.2%) had received a liver transplant, and time to liver transplantation was on average 29.56 months from the initial diagnosis. They all had the Val30Met mutation. The organs of the nervous system were those most frequently impaired (57.3%), and 83.9% of the symptomatic patients were fully ambulant (stage 1). Family history was reported in 69.3% of the cases, with the patient’s father being the most commonly affected relative. Comorbidities were frequent, with high blood pressure being the most common.

Conclusions

Our findings provide additional information on this condition and are useful for describing the demographic features, clinical presentation, diagnosis, and natural course of TTR-FAP in Majorca.